Vitreous clay conduit section



April 1, 1941. A, MCDONALD 2,236,802

VITREOUS CL AY CONDUIT SECTION Filed March 15, 1939 I 2 Sheets-Sheet l ALBERT P. M Dan/ALB [v Vf/VI'QE April 1, 1941. A, P, McDONALD V 2,236,802

VITREOUS CLAY CONDUIT SECTION Filed March 13, 1939 2 Sheets-Sheet 2 4. v Fly. 3

flLBERT 1 M DO INVENTOR Patented Apr. 1, 1941 UNITED STATES PATENT OFFICE 1 Claim.

In vitreous clay conduits of the character largely used underground to encase the piping of steam-transmission, electrical wiring and other systems, it is customary to ship the conduits in the form of short cylindrical sections which, at the job, are split longitudinally into upper and lower halves. The lower halves are successively laid end to end on the upper surface of a sectional base drain resting upon the floor of the trench in which the conduit is to be buried. The upper halves are placed over and cemented or otherwise secured to the lower halves, after the pipes, pipe supports, and insulating material have been installed, whereupon the trench is filled in.

The present invention relates to improvements in the pipe supports. One Widely used pipe-supporting arrangement is indicated in the Gray Patent #1,110,12'7. In it, the lower half of a conduit section is provided, along each upwardly curving inner-side wall portion, with .a longitudinally directed rib of triangular cross section. Each rib is provided with correspondingly positioned notches to receive and support the opposite ends of a pipe-supporting cradle member. The cradle member, which is of semicircular shape, is bridged by a rod which carries rollers upon which the pipes are slidably supported. While that arrangement has enjoyed wide use, the cradle member is subject to displacement at times from its proper position. In addition, I have found that the point supports which it affords at the notches are responsible, in some measure, to conduit breakages heretofore attributed to other causes.

The principal object of the present invention is to improve this form of support and, more particularly, to secure greater stability and better load distribution to the end of overcoming the objections above noted.

A further object is to provide a simple, practical and effective arrangement which is inexpensive to make and easily installed.

The invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a perspective of a proposed conduit section;

Figure 2 is a radial section through the plane of the rib recesses shown in Figure 1;

Figure 3 is a plan view of the proposed cradle member as installed in the conduit;

Figure 4 is an end elevation of the arrangement shown in Figure 2 with the pipe-supporting rod and rollers in place, this view being partly broken for the sake of clearness; and

Figure 5 is a fragmentary section taken along line 55 of Figure 4.

The drawings conventionally illustrate a conduit section I of cylindrical shape having the usual bell-and-spigot ends. In accordance with customary practice, this section should be provided with longitudinally arranged diametrically opposed score lines to facilitate its separation at the job into upper and lower halves. The lower half is conventionally provided, at its opposite sides, with longitudinal ribs 2, triangular in cross section.

In accordance with my invention, these ribs, instead of being notched to form pockets, are radially cut at corresponding points to form opposed segment" recesses 3 which extend continuously from the horizontal upwardly facing surface of the rib to the vertical laterally facing surface thereof. The segmen recess 3 preferably extends entirely through the rib so that its outer or bottom surface forms a continuation of the wall curvature of the lower half of the section.

To support the pipes of the conduit, a cradle member 4, of conventional semicircular shape, is provided. This member also is conventionally provided with opposed steps upon any opposed pair of which a pipe-supporting rod 5 with rollers 6 may rest. In accordance with the present invention, however, the cradle member 4 is arranged to extend through the recesses of opposed ribs and to fit closely against the wall of the con duit substantially throughout its semicircular extent. The cradle member is additionally provided, adjacent each of its ends, with a pair of oppositely and axially directed arms 1 positioned either to engage lightly or to clear slightly the horizontal upwardly facing surfaces of the rib on either side of the cradle. 1

With this arrangement, the radial end surfaces of each rib, which form the side walls of each segmen recess 3, cooperate to prevent the cradle from being twisted about a vertical axis or axially displaced. The cradle arms cooperate to prevent the cradle from being tilted about a horizontal axis. As a consequence, the cradle is firmly retained in its proper position, although removably mountedtherein. With substantial contact between thecradle and the conduit throughout the semicircular length of the cradle, the concentration of the load at one or more of a small number of points is entirely avoided, and the distribution of that load, through an infinite number of points over substantially the entire bottom-face area of the cradle, is secured. With such distribution of load, sharp blows, to which the cradle member may be subjected as a result of water hammer and the like, are communicated to the conduit over a wide area instead of being concentrated at a few points. In this way, breakages are minimized.

With a cradle bridging the inner-wall conduit curvature, as heretofore, the space between the bottom of the cradle and the underlying portion of the conduit wall is not usable to any advantage. With my arrangement of the cradle, however, the dead space below the cradle is reduced to a minimum, while the usable space above the cradle is increased to a maximum. This has the important advantage of minimizing the size, hence the cost, of a conduit for any given number or size of encased pipes.

Having described my invention, I claim:'

In a conduit system: a longitudinal open-ended tubular body having upper and lower halves; a pair of ribs longitudinally directed along and integrally formed on opposed upwardly curving inner side-wall portions of the lower half, each rib having correspondingly positioned segment recesses; and a pipe-supporting cradle member transversely arranged within the lower half to extend through opposed segment recesses, said member having a semicircular peripheral face in substantially full engagement with the wall of the lower half and. being provided adjacent each end with a pair of oppositely disposed axially directed arms positioned to extend closely adjacent the upper side of adjacent rib portions forming opposite sides of the segment recess.

ALBERT P. MCDONALD. 

